Tetrahydro-pyrazolo[1,5-a]pyrido-pyrimidines as antagonists of serotonin 5-HT6 receptors, methods for the production and use thereof

ABSTRACT

The present invention relates to serotonin 5-HT 6  receptor antagonists-novel substituted 3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidines and substituted 3-sulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidines, drug substances and pharmaceutical compositions comprising drug substances as the mentioned above compounds and to the method of prophylaxis and treatment of various conditions and diseases of central nervous system in humans and warm-blooded animals pathogenesis of which is associated with serotonin 5-HT 6  receptors. 
     In formulas 1 and 2 
                         
Ar is optionally substituted aryl or optionally substituted heterocyclyl; R 1  is hydrogen, optionally substituted lower C 1 -C 3  alkyl, substituted hydroxyl group, substituted sulfanyl group; R 2  is hydrogen or optionally substituted C 1 -C 3  alkyl; R 3  is hydrogen, optionally substituted C 1 -C 3  alkyl or tert.-butyloxycarbonyl.

FIELD OF THE INVENTION

The invention relates to the novel arylsulfonyl-azaheterocyclic compounds, to novel serotonin 5-HT₆ receptor antagonists, novel drug substances, pharmaceutical compositions, medicaments and methods for preparation thereof. More particular, the present invention is directed to serotonin 5-HT₆ receptor antagonists-novel substituted 3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidines and substituted 3-sulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidines, drug substances and pharmaceutical compositions comprising the said compounds as active ingredients, and to methods of prophylaxis and treatment of various conditions and diseases of central nervous system pathogenesis of which is associated with 5-HT₆ receptors in humans and warm-blooded animals.

BACKGROUND OF THE INVENTION

The origin of pharmacological effect of novel drug substances is their ability to interact with serotonin 5-HT₆ receptors playing the key role in treatment of central nervous system diseases (CNS), in particular, Alzheimer's disease (AD), Huntington's disease, schizophrenia, other neurodegenerative diseases, cognitive disorders and obesity.

Usefulness of selective antagonists of serotonin 5-HT₆ receptors for treating of CNS diseases, in particular, schizophrenia, AD and other neurodegenerative diseases and cognitive disorders was conclusively proved in preclinical investigation and is regarded to be very perspective in medicine of future. [Holenz J., Pauwels P. J., Diaz J. L., Merce R., Codony X., Buschmann H. Medicinal chemistry strategies to 5-HT₆ receptor ligands as potential cognitive enhancers and antiobesity agents. Drug Disc. Today. 2006; 11:283-299]. At mammals these receptors are localized exclusively in central nervous system (CNS), and mainly in parts of brain responsible for training and memory. [Ge'rard C., Martres M.-P., Lefe'vre K., Miguel M.-C., Verge' D., Lanfumey L., Doucet E., Hamon M., El Mestikawy S. Immuno-localisation of serotonin 5-HT₆ receptor-like material in the rat central nervous system. Brain Research. 1997; 746:207-219]. Besides, it was shown [Dawson L. A., Nguyen H. Q., Li P. The 5-HT(6) receptor antagonist SB-271046 selectively enhances excitatory neurotransmission in the rat frontal cortex and hippocampus. Neuropsychopharmacology. 2001; 25:662-668], that 5-HT₆ receptors are modulators of the whole number of neuromediator systems including cholinergic, noradrenergic, glutamatergic and dopaminergic. Taking into account the fundamental role of these systems in normal cognitive processes and their dysfunction at neurodegeneration, exclusive role of 5-HT₆ receptors in forming normal and “pathological” memory becomes obvious.

In a large number of nowadays publications it was shown that blocking of 5-HT₆ receptors leads to considerable enhancement of memory consolidation in various animal models of training-memorizing-reproduction [Foley A. G., Murphy K. J., Hirst W. D., Gallagher H. C., Hagan J. J., Upton N., Walsh F. S., Regan C. M. The 5-HT(6) receptor antagonist SB-271046 reverses scopolamine-disrupted consolidation of a passive avoidance task and ameliorates spatial task deficits in aged rats. Neuropsychopharmacology. 2004; 29:93-100; Riemer C., Borroni E., Levet-Trafit B., Martin J. R., Poli S., Porter R. H., Bos M. Influence of the 5-HT6 receptor on acetylcholine release in the cortex: pharmacological characterization of 4-(2-bromo-6-pyrrolidin-1-ylpyridine-4-sulfonyl)phenylamine, a potent and selective 5-HT₆ receptor antagonist. J. Med. Chem. 2003; 46:1273-1276; King M. V., Woolley M. L., Topham I. A., Sleight A. J., Marsden C. A., Fone K. C. 5-HT6 receptor antagonists reverse delay-dependent deficits in novel object discrimination by enhancing consolidation e an effect sensitive to NMDA receptor antagonism. Neuropharmacology 2004; 47:195-204]. It was also demonstrated that considerable enhancement of cognitive functions in aged rats took place under the action of 5-HT₆ receptor antagonists in Morrison's water maze experiment [Foley A. G., Murphy K. J., Hirst W. D., Gallagher H. C., Hagan J. J., Upton N., Walsh F. S., Regan C. M. The 5-HT(6) receptor antagonist SB-271046 reverses scopolamine-disrupted consolidation of a passive avoidance task and ameliorates spatial task deficits in aged rats. Neuropsychopharmacology. 2004; 29:93-100]. Recently more thorough understanding of 5-HT₆ receptor function in cognitive processes and more accurate conceptions concerning possible pharmacophoric properties of their antagonists were achieved. [Holenz J., Pauwels P. J., Diaz J. L., Merce R., Codony X., Buschmann H. Medicinal chemistry strategies to 5-HT₆ receptor ligands as potential cognitive enhancers and antiobesity agents. Drug Disc. Today. 2006; 11:283-299]. This resulted in preparation of highly affine selective ligands (“molecular tools”), and later to clinical candidates. At present a number of 5-HT₆ receptor antagonists are at various phases of clinical investigation as potential drug substances for treatment of AD, Huntington's disease, schizophrenia (antipsychotic) and other neurodegenerative and cognitive diseases (Table 1) [http://integrity.prous.com].

TABLE 1 5-HT₆ Receptor antagonists as drug candidates. Clinical phase Medicament of testing Developer Therapeutic group Dimebon ™ Phase III Medivation (USA) Alzheimer's disease treatment SGS-518 Phase II Lilly, Saegis Cognitive diseases treatment SB-742457 Phase II GlaxoSmithKline Alzheimer's disease treatment; Antipsychotic Dimebon* Phase I/IIa Medivation (USA) Huntington's disease treatment Dimebon* Phase II (Russia) Schizophrenia PRX-07034 Phase I Epix Pharm. Obesity treatment; Antipsychotic; Cognitive diseases treatment SB-737050A Phase II GlaxoSmithKline Antipsychotic BVT-74316 Phase I Biovitrum Obesity treatment SAM-315 Phase I Wyeth Pharm. Alzheimer's disease treatment SYN-114 Phase I Roche, Synosis Cognitive diseases Ther. treatment BGC-20-761 Preclinical BTG (London) Antipsychotic; Cognitive diseases treatment FMPO Preclinical Lilly Antipsychotic Dimebon ™ Preclinical (Russia) Insult treatment

Another attractive property of 5-HT₆ receptor antagonists is their ability to suppress appetite that can lead to the development on their basis of essentially novel remedies for overweight lowering and obesity treatment. [Vicker S. P., Dourish C. T. Serotonin receptor ligands and the treatment of obesity. Curr. Opin. Investig. Drugs. 2004; 5:377-388]. This effect was confirmed in many investigations [Holenz J., Pauwels P. J., Diaz J. L., Merce R., Codony X., Buschmann H. Medicinal chemistry strategies to 5-HT₆ receptor ligands as potential cognitive enhancers and antiobesity agents. Drug Disc. Today. 2006; 11:283-299. Davies S. L. Drug discovery targets: 5-HT₆ receptor. Drug Future. 2005; 30:479-495], its mechanism is based on suppression of γ-aminobutyric acid signaling by 5-HT₆ receptor antagonists and increasing of α-melanocyte-stimulating hormone emission, that, finally, results in lowering of food demand [Woolley M. L. 5-ht6 receptors. Curr. Drug Targets CNS Neurol. Disord. 2004; 3:59-79]. Now two antagonists of 5-HT₆ receptors are at the first phase of clinical testing as drug candidates for obesity treatment (Table 1) [http://integrity.prous.com].

In this context searching for new selective and effective serotonin 5-HT₆ receptor antagonists seems to be original and perspective approach to the development of novel drug substances for treating of a great number of neurological and neurodegenerative diseases and cognitive disorders.

There are many publications in scientific literature concerning various biologically active sulfonyl substituted azaheterocycles, among them ligands of serotonin receptors. For example, substituted 1-(2-aminoethyl)-4-(arylsulfonyl)pyrazoles of general formula A1 were described as serotonin 5-HT_(2c) receptor ligands [WO 2003057674 A1] and substituted 7-amino-3-(sulfonyl)pyrazolo[1,5-a]pyrimidines A2 as serotonin 5-HT₆ receptor antagonists [EP 941994 A1, 1999]

A1: Ar=alkyl, aryl; R¹ and R²=H, OH, alkyl, alkoxy; R³ and R⁴=H, alkyl, aryl. A2: Ar=aryl, heterocyclyl; R¹=H, alkyl, alkylthio; R²=H, alkyl, halogen; R³=H, alkyl, hydroxyalkyl; R⁴ and R⁵=H; NR⁴R⁵=piperazinyl.

With the aim of working out novel highly effective neuroprotective medicaments the authors of the invention carried out widespread investigation in the field of substituted 3-(sulfonyl)pyrazolo[1,5-a]pyrimidines, as a result of which novel drug substances which were 5-HT₆ receptor antagonists were found.

DISCLOSURE OF THE INVENTION

In the context of the invention, the terms are generally defined as follows:

“Agonists” mean ligands being bound to receptors of definite type actively promote transferring their specific signal and by that cause the biological response of the cell.

“Alkyl” means an aliphatic hydrocarbon straight or branched group with 1-12 carbon atoms. Branched means an alkyl chain with one or more “lower alkyl” substituents. Alkyl group may have one or more substituents of the same or different structure (“alkyl substituent”) including halogen, alkenyloxy, cycloalkyl, aryl, heteroaryl, heterocyclyl, aroyl, cyano, hydroxy, alkoxy, carboxy, alkynyloxy, aralkoxy, aryloxy, aryloxycarbonyl, alkylthio, heteroarylthio, aralkylthio, arylsulfonyl, alkylsulfonylheteroaralkyloxy, annelated heteroarylcycloalkenyl, annelated heteroarylcycloalkyl, annelated heteroarylheterocyclenyl, annelated heteroarylheterocyclyl, annelated arylcycloalkenyl, annelated arylcycloalkyl, annelated arylheterocyclenyl, annelated arylheterocyclyl, alkoxycarbonyl, aralkoxycarbonyl, heteroaralkyloxycarbonyl or R_(k) ^(a)R_(k+1) ^(a)N—, R_(k) ^(a)R_(k+1) ^(a)NC(═O)—, R_(k) ^(a)R_(k+1) ^(a)NC(═S)—, R_(k) ^(a)R_(k+1) ^(a)NSO₂—, where R_(k) ^(a) and R_(k+1) ^(a) independently of each other represent “amino group” substituent, the meanings thereof which are defined in this section, for example, hydrogen, alkyl, aryl, aralkyl, heteroaralkyl, heterocyclyl or heteroaryl, or R_(k) ^(a) and R_(k+1) ^(a) together with the N-atom, they are attached to, form through R_(k) ^(a) and R_(k+1) ^(a) 4-7-membered heterocyclyl or heterocyclenyl. The preferred alkyl groups are methyl, trifluoromethyl, cyclopropylmethyl, cyclopentylmethyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, n-pentyl, 3-pentyl, methoxyethyl, carboxymethyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, benzyloxycarbonylmethyl and pyridylmethyloxycarbonylmethyl. The preferred “alkyl substituents” are cycloalkyl, aryl, heteroaryl, heterocyclyl, hydroxy, alkoxy, alkoxycarbonyl, aralkoxy, aryloxy, alkylthio, heteroarylthio, aralkylthio, alkylsulfonyl, arylsulfonyl, alkoxycarbonyl, aralkoxycarbonyl, heteroaralkyloxycarbonyl or R_(k) ^(a)R_(k+1) ^(a)N—, R_(k) ^(a)R_(k+1) ^(a)NC(═O)—, annelated arylheterocyclenyl, annelated arylheterocyclyl. “Alkoxy” means an alkyl-O-group, wherein alkyl is defined in this section. The preferred alkoxy groups are methoxy, ethoxy, n-propoxy, iso-propoxy and n-butoxy. “Alkyloxycarbonyl” means an alkyl-O—C(═O) group, wherein alkyl is defined in this section. The representatives of alkyloxycarbonyl are: methoxycarbonyl, ethoxycarbonyl, n-butoxycarbonyl, iso-propoxycarbonyl, benzyloxycarbonyl and phenethyloxycarbonyl. “Alkylthio or Alkylsulfanyl” means alkyl-S-group, wherein the meaning of alkyl is defined in this section. “Anxiolytic” (tranquilizer) means a medicament intended for treatment of anxious disorders. “Antagonists” mean ligands being bound to definite receptors do not cause active cellular responses. Antagonists prevent linkage between agonists and receptors and by that block specific receptor signal transmission. “Antidepressant” means a medicament intended for treating depression. “Antipsychotic” means a remedy intended for treatment of psychotic diseases. “Aryl” means an aromatic mono- or polycyclic system with 6-14 carbon atoms, predominantly from 6 to 10 C-atoms. Aryl may have one or more “cyclic system substituents” of the same or different structure. Phenyl, substituted phenyl, naphthyl, or substituted naphthyl are the representatives of aryl groups. Aryl could be annelated with nonaromatic cyclic system or heterocycle. “Arylsulfonyl” means aryl-SO₂-group, wherein the meaning of aryl is defined in this section. “Acyl” means H—C(═O)— or alkyl-C(═O)—, cycloalkyl-C(═O)—, heterocyclyl-C(═O)—, heterocyclylalkyl-C(═O)—, aryl-C(═O)—, arylalkyl-C(═O)—, heteroaryl-C(═O)—, heteroarylalkyl-C(═O)— groups, wherein alkyl-, cycloalkyl-, heterocyclyl-, heterocyclylalkyl-, aryl-, arylalkyl-, heteroaryl-, heteroarylalkyl- are defined in this section. “Acylamino” means acyl-NH-group, wherein the meaning of acyl is defined in this section. “Halogen” means fluorine, chlorine, bromine and iodine. Preference is given to fluorine, chlorine and bromine. “Hydrate” means stoichiometric or nonstoichiometric compositions of the compounds or their salts with water. “Depression” means big depression; incidental, chronic and recurring form of big depression; dysthymic disorder (dysthymia); cyclotymia; affective disorder; syndrome of seasonal affective disorder; bipolar disorder, including bipolar disorders of I and II type; and other depressive disorders and conditions. Depression also means the depressions accompanying AD, vascular dementia; disorder of mood induced by alcohol and substances; schizoaffective disorder of depressive type; disorder of adaptation. Except for that, depression includes depression of oncological patients; depression at Parkinson's disease; depressions after myocardial infarction; depressions of fruitless women; pediatric depression; postnatal depression; the depressions accompanying somatic, neuralgic and other diseases “Substituent” means a chemical radical attached to scaffold (fragment), for example, “alkyl substituent”, “amino group substituent”, “carbamoyl substituent”, and “cyclic system substituent”, the meanings thereof are defined in this section. “Cognitive disorders or disorders of cognitive functions” mean disorders (weakening) of mental abilities including attentiveness, memory, mentality, cognition, education, verbal, mental, executive and creative abilities, time and space orientation; in particular, cognitive disorders associated with AD, Parkinson's and Huntington's diseases, senile dementia; age-associated memory impairment, AAMI; dysmetabolic encephalopathy; psychogenous memory impairment; amnesia; amnesic disturbances; transit global amnesia; dissociative amnesia; vascular dementia; light or mild cognitive impairment (MCI); attention deficit hyperactivity disorder (AD/HD); cognitive impairments, accompanying psychotic diseases, epilepsy, delirium, autism, psychosis, Down's syndrome, bipolar disorders and depression; AIDS-associated dementia; dementias at hypothyroidism; dementia connected with alcohol, substances causing dependability and neurotoxins; dementia accompanying neurodegenerative diseases, for example, cerebellar degeneracy and amyotrophic lateral sclerosis; cognitive disturbances connected with cerebral crisis, infectious and oncological brain diseases as well as traumatic brain injury; cognitive function damages associated with autoimmune and endocrine diseases, and others. “Drug substance” means a physiologically active compound of synthetic or other (biotechnological, vegetable, animal, microbe and so on) origins exhibiting pharmacological activity which is an active ingredient of pharmaceutical composition employed in production and preparation of medicaments. “Medicament” —is a compound or a mixture of compounds representing pharmaceutical composition in the form of tablets, capsules, injections, ointments and other drug products intended for restoration, improvement or modification of physiological functions at humans and animals, and for treatment and prophylaxis of diseases, diagnostics, anesthesia, contraception, cosmetology and others. “Ligands” (from Latin ligo) represent chemical compounds (small molecule, peptide, protein, inorganic ion, and so on) capable to interact with receptors which convert this interaction into specific signal. “Neurodegenerative diseases” mean specific conditions and diseases, accompanied by damage and primary destruction of nervous cell populations in certain areas of central nervous system. Neurodegenerative diseases include but are not limited by: AB; Parkinson's and Huntington's diseases (chorea); multiocular sclerosis; cerebellar degeneracy; amyotrophic lateral sclerosis; dementias with Lewy bodies; spinal muscular atrophy; peripherical neuropathy; spongy encephalitis (Creutzfeld-Jakob Disease); AIDS dementia; multi-infract dementia; frontotemporal dementias; leukoencephalopathy (spongy degeneration of white matter); chronic neurodegenerative diseases; cerebral crisis; ischemic, reperfusion and hypoxic brain damage; epilepsy; cerebral ischemia; glaucoma; traumatic brain injury; Down's syndrome; encephalomyelitis; meningitis; encephalitis; neuroblastoma; schizophrenia; depression. Moreover, neurodegenerative diseases include pathological states and disorders associated with hypoxia, substance abuse, causing dependability, under neurotoxins influence; infectious and oncological brain diseases as well as neuronal damages associated with autoimmune and endocrine diseases and others. “Nootrops” or “Nootropics” (neurometabolic stimulates) are medicaments taken for cognition enhancing. “Psychic disorders, (psychic diseases)” are diseases or diseased states associated with mental disturbance and/or mentality frustration. “Psychic disorders” include affective disorders (bipolar affective disorders, big depression, hypomania, minor depression, maniacal syndrome, Cotard's syndrome, cyclothymia, schizoaffective disorders and so on), intellectual-mnestic disorders; manias (hypomania, graphomania, kleptomania, compulsive shopping, mania of persecution, pornographomania, erotomania and so on); disorder of multiple personality, amentia, alcoholomania, deliration, delirium syndrome, hallucinosis, hallucinations, lucinatory effects, homicidomania, delirium; illusion, querulous paranoiaclinical lycanthropy, macropsia, antagonistic delusion, micropsia, narcomania; anorexia nervosa, oneiroid syndrome, paranoid, paranoia, paraphrenia, pseudohallucinations, psychosis, Cotard's syndrome, schizoaffective disorder, schizotypical disorder, schizophrenia, schizoaffective psychosis disorder, schizophrenomorphic disorder, Shrebera's syndrome, Daniel Paul's syndrome), phobias (agarophobia, arachnephobia, autophobia, verminophobia, hydrosophobia, hydrophobia, demophobia, zoophobia, carcinophobia, claustrophobia, climacophobia, xenophobia, misophobia, radiophobia, photophobia; skoliephobia, scotophobia, social phobia, tetraphobia, triskaidekaphobia, erotophobia); alcoholic psychosis, alcoholic palimpsest, allotriophagy, aphasia, graphomania, dissociative fugue state, dissociative disorders; dysphorias, internet-dependences, hypochondria, hysteria, kopophobia, delirium of persecution, melancholy, misanthropy, obsession, panic attacks, Asperger's syndrome, Capgras' syndrome, Munchausen's syndrome, Retta's syndrome, Fregoly's syndrome, syndrome of attention and hyperactivity deficit, obsessive-compulsive disorder, syndrome of chronic narcotization consequences, syndrome of psychic automatism, syndrome of infantile autism, madness, taphophilia, anxiety conditions, Hikikomory's syndrome, erotographomania and so on. “Psychotic diseases” are all types of schizophrenia; schizoaffective psychosis; schizotypical disorders; schizoaffective disorders, including bipolar and depressive types; delirious disorders including reference delusion, delusion of persecution, megalomania, delusion of jealousy, erotomania, and also hypochondriacal, somatic, mixed and not differentiated delirium; short-time psychotic disorders; induced psychotic frustration; induced by substances psychotic frustration; and other psychotic disorders. “Receptors” (from Latin recipere) represent biological macromolecules located either on cytoplasm membrane of cell or intracellular, capable specifically interact with restricted number of physiologically active compounds (ligands) and transform the signal of this interaction into definite cellular response. “Sulfanyl” means R—S-group, wherein R represents alkyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, annelated heteroarylcycloalkenyl, annelated heteroarylcycloalkyl, annelated heteroarylheterocyclenyl, annelated heteroarylheterocyclyl, annelated arylcycloalkenyl, annelated arylcycloalkyl, annelated arylheterocyclenyl, annelated arylheterocyclyl, the meanings of which are defined in this section. “Sulfonyl” means R—SO₂-group in which R represents alkyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, annelated heteroarylcycloalkenyl, annelated heteroarylcycloalkyl, annelated heteroarylheterocyclenyl, annelated heteroarylheterocyclyl, annelated arylcycloalkenyl, annelated arylcycloalkyl, annelated arylheterocyclenyl, annelated arylheterocyclyl the meanings of which are defined in this section. “Therapeutic kit” is a simultaneously administered combination of two or more drug substances with different mechanism of pharmacological action and aimed at different biotargets taking part in pathogenesis of the disease. “Anxiety disorders” means generalized (inconcrete) anxiety; acute uncontrolled anxiety; panic disorder; phobia, for example, agoraphobia (acute fear of crowded place) or social (acute fear of humiliation at presence of other people) or any other phobia (acute fear of particular subjects, animals or situations, in the form of phobia of height, of medical procedures, lifts, open space etc.); an obsessional condition (obsessive-compulsive disorder); posttraumatic stress disorder and acute stress disorder. Besides, anxiety disorders include anxiety conditions induced by alcohol or substances; anxiety under adaptation; as well as mixed forms of anxiety disorders and depression. “Schizophrenia” means all known types, forms and variants of the disease, including: simple, hebephrenic, paranoid, hypertoxic (pyretic), catatonic, schizoaffective, residual or not differentiated schizophrenia and/or the forms of schizophrenia defined in classification of American Psychiatric Association (American Psychiatric Association; in: Diagnostic and Statistical Manual of Mental Disorders, IV Edition, Washington D.C. 2000) or in International classification (International Statistical Classification of Diseases and Related Health Problems) or any other known forms. “Pharmaceutical composition” means a composition comprising, at least, one of compounds of general formula 1 or 2 and, at least, one of components selected from pharmaceutically acceptable and pharmacologically compatible fillers, solvents, diluents, auxiliary, distributing and sensing agents, delivery agents, such as preservatives, stabilizers, disintegrators, moisteners, emulsifiers, suspending agents, thickeners, sweeteners, flavoring agents, aromatizing agents, antibacterial agents, fungicides, lubricants, and prolonged delivery controllers, the choice and suitable proportions of which depend on the nature and way of administration and dosage. Examples of suitable suspending agents are: ethoxylated isostearyl alcohol, polyoxyethene, sorbitol and sorbitol ether, microcrystalline cellulose, aluminum metahydroxide, bentonite, agar-agar and tragacant and mixtures thereof as well. Protection against microorganism action can be provided by various antibacterial and antifungal agents, such as: parabens, chlorobutanol, sorbic acid, and similar compounds. Composition may also contain isotonic agents, such as: sugar, sodium chloride, and similar compounds. Prolonged effect of the composition may be achieved by agents slowing down absorption of the active ingredient, for example, aluminum monostearate and gelatin. Examples of suitable carriers, solvents, diluents and delivery agents include water, ethanol, polyalcohols and their mixtures, natural oils (such as olive oil) and injection-grade organic esters (such as ethyl oleate). Examples of fillers are: lactose, milk-sugar, sodium citrate, calcium carbonate, calcium phosphate and the like. Examples of disintegrators and distributors are: starch, alginic acid and its salts, and silicates. Examples of suitable lubricants are: magnesium stearate, sodium lauryl sulfate, talc and polyethylene glycol of high molecular weight. Pharmaceutical composition for peroral, sublingval, transdermal, intramuscular, intravenous, subcutaneous, local or rectal administration of active ingredient, alone or in combination with another active compound may be administered to humans and animals in standard administration form, or in mixture with traditional pharmaceutical carriers. Suitable standard administration forms include peroral forms such as tablets, gelatin capsules, pills, powders, granules, chewing-gums and peroral solutions or suspensions, for example, therapeutic kit; sublingval and transbuccal administration forms; aerosols; implants; local, transdermal, subcutaneous, intramuscular, intravenous, intranasal or intraocular forms and rectal administration forms. “Pharmaceutically acceptable salt” means relatively nontoxic both organic and inorganic salts of acids and bases disclosed in this invention. Salts could be prepared in situ in processes of synthesis, isolation or purification of compounds or they could be prepared specially. In particular, salts of bases could be prepared starting from purified bases disclosed in the invention and suitable organic or mineral acid. Examples of salts prepared in this manner include hydrochlorides, hydrobromides, sulfates, bisulfates, phosphates, nitrates, acetates, oxalates, valeriates, oleates, palmitates, stearates, laurates, borates, benzoates, lactates, p-toluenesulfonates, citrates, maleates, fumarates, succinates, tartrates, methane sulphonates, malonates, salicylates, propionates, ethane sulphonates, benzene sulfonates, sulfamates and the like (Detailed description of such salt properties is given in: Berge S. M., et al., “Pharmaceutical Salts” J. Pharm. Sci., 1977, 66: 1-19). Salts of disclosed acids may be prepared by reaction of purified acids specifically with suitable base; moreover, metal salts and amine salts may be synthesized too. Metal salts are salts of sodium, potassium, calcium, barium, magnesium, lithium and aluminum; sodium and potassium salts being preferred. Suitable inorganic bases from which metal salts can be prepared are: sodium hydroxide, carbonate, bicarbonate and hydride; potassium hydroxide, carbonate and bicarbonate, lithium hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide. Organic bases suitable for preparation of disclosed acid salts are amines and amino acids the basicity of which is sufficient enough to produce stable salt and suitable for use in medical purposes (in particular, they are to have low toxicity). Such amines include ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, benzylamine, dibenzylamine, dicyclohexylamine, piperazine, ethylpiperidine, tris(hydroxymethyl)aminomethane and the like. Besides, salts can be prepared using some tetraalkylammonium hydroxides, such as holine, tetramethylammonium, tetraethylammonium, and the like. Amino acids may be selected from the main aminoacids—lysine, ornithine and arginine.

The subject of the present invention is the novel compounds—substituted 3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidines of the general formula 1 and substituted 3-sulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidines of the general formula 2 and pharmaceutically acceptable salts and/or hydrates thereof.

wherein: Ar represents optionally substituted aryl or optionally substituted heterocyclyl; R¹ represents hydrogen, optionally substituted lower C₁-C₃ alkyl, substituted hydroxyl group, substituted sulfanyl group; R² represents hydrogen or optionally substituted C₁-C₃ alkyl; R³ represents hydrogen, optionally substituted C₁-C₃ alkyl or tert.-butyloxycarbonyl.

The preferred novel compounds are substituted 3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidines of the general formula 1.1 and substituted 3-phenylsulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidines of the general formula 2.1 and pharmaceutically acceptable salts and/or hydrates thereof.

wherein: R¹, R² and R³ have the above meanings; R⁴ represents hydrogen, one or two optionally identical halogens, hydroxyl group optionally substituted with C₁-C₃ alkyl.

The preferred novel compounds are substituted 2-methylsulfanyl-3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidines of the general formula 1.2 and substituted 2-methylsulfanyl-3-sulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidines of the general formula 2.2 and pharmaceutically acceptable salts and/or hydrates thereof

wherein: R², R³ and R⁴ are all as mentioned above;

The preferred novel compounds are 2-methyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(1), 2,5-dimethyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(2), 2,7-dimethyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(3), 2,5,7-trimethyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(4), 2-methyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(5), 2,5-dimethyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(6), 2,7-dimethyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(7), 2,5,7-trimethyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(8), 2-methylsulfanyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(1), 5-methyl-2-methylsulfanyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(2), 7-methyl-2-methylsulfanyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(3), 5,7-dimethyl-2-methylsulfanyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(4), 2-methylsulfanyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(5), 5-methyl-2-methylsulfanyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(6), 7-methyl-2-methylsulfanyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(7), 5,7-dimethyl-2-methylsulfanyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(8) and pharmaceutically acceptable salts and/or hydrates thereof.

The subject of the present invention is also a method for the preparation of novel substituted 3-sulfonyl-tetrahydropyrazolo[1,5-a]pyrido-pyrimidines of the general formulas 1 and 2 by interaction of 3-amino-4-sulfonyl-2H-pyrazoles of the general formula 3 with β-diketones of the general formula 4 and subsequent isolation or separation of compounds 1 and 2 according to the scheme given below.

wherein: Ar, R¹, R² and R³ are all as mentioned above.

The subject of the present invention is the development of novel serotonin 5-HT₆ receptor antagonists.

The subject in view is achieved by serotonin 5-HT₆ receptor antagonists, which are substituted 3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidines of the general formula 1 and substituted 3-sulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidines of the general formula 2 and pharmaceutically acceptable salts and/or hydrates thereof.

The subject of the present invention is also a drug substance for pharmaceutical compositions and medicaments representing at least one 3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine of the general formula 1,3-sulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidine of the general formula 2 and pharmaceutically acceptable salt and/or hydrate thereof.

The subject of the present invention is also a pharmaceutical composition interacting with serotonin 5-HT₆ receptors for prophylaxis and treatment of various conditions and diseases of CNS in humans and warm-blooded animals comprising a pharmaceutically effective amount of a novel drug substance representing at least one of 3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidines of the general formula 1 or 3-sulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidines of the general formula 2 and pharmaceutically acceptable salts and/or hydrates thereof.

Pharmaceutical compositions may include pharmaceutically acceptable excipients. Pharmaceutically acceptable excipients mean diluents, auxiliary agents and/or carriers applied in the sphere of pharmaceutics. According to the invention a pharmaceutical composition together with a drug substance of general formulas 1, 2 may include other active ingredients provided that they do not give rise to undesirable effects, such as allergic reactions.

If needed, according to the present invention pharmaceutical compositions could be used in clinical practice in various forms prepared by mixing the said compositions with traditional pharmaceutical carries, for example, peroral forms (such as, tablets, gelatinous capsules, pills, solutions or suspensions); forms for injections (such as, solutions or suspensions for injections, or a dry powder for injections which requires only addition of water for injections before utilization); local forms (such as, ointments or solutions).

According to the present invention the carriers used in pharmaceutical compositions represent carriers which are used in the sphere of pharmaceutics for preparation of commonly used forms. Binding agents, greasing agents, disintegrators, solvents, diluents, stabilizers, suspending agents, colorless agents, taste flavors are used for peroral forms; antiseptic agents, solubilizers, stabilizers are used in forms for injections; base materials, diluents, greasing agents, antiseptic agents are used in local forms.

The subject of the present invention is also a method for the preparation of novel pharmaceutical composition by mixing with inert excipient and/or solvent of a drug substance which is at least one of 3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidines of the general formula 1 or 3-sulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidines of the general formula 2 or pharmaceutically acceptable salts and/or hydrates thereof.

The subject of the present invention is also a medicament in the form of tablets, capsules, or injections, placed in pharmaceutically acceptable packing including a drug substance which is at least one of 3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidines of the general formula 1 or 3-sulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidines of the general formula 2 and pharmaceutically acceptable salts and/or hydrates thereof, or a pharmaceutical composition comprising the said drug substance, intended for prophylaxis and treatment of pathological conditions and diseases of CNS, pathogenesis of which is associated with dysfunction of 5-HT₆ receptors activation.

According to the invention the preferable medicament is a medicament intended for treatment and prophylaxis of cognitive disorders and neurodegenerative disease.

According to the invention the preferable medicament is a medicament intended for treatment and prophylaxis of Alzheimer's disease and Huntington's diseases.

According to the invention the preferable medicament is a medicament intended for treatment and prophylaxis of psychotic disorders and schizophrenia.

According to the invention the preferable medicament is a medicament, representing a nootropic for mental ability enhancing.

According to the invention the preferable medicament is a medicament, representing an anxiolytic for treatment and prophylaxis of anxiety states and disorders.

According to the invention the preferable medicament is also a medicament for treatment and prophylaxis of obesity.

The subject of the present invention is a therapeutic kit intended for treatment and prophylaxis of various diseases pathogenesis of which is associated with serotonin 5-HT₆ receptors in humans and animals, including a novel drug substance, which is at least one 3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine of the general formula 1 or 3-sulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidine of the general formula 2 or pharmaceutically acceptable salt and/or hydrate thereof, or a novel pharmaceutical composition, comprising the said drug substance, or a novel medicine, containing the said novel drug substance, or a novel pharmaceutical composition.

According to the invention the preferable therapeutic kit is a therapeutic kit for treatment and prophylaxis of neurological disorders, neurodegenerative and cognitive diseases in humans and animals comprising a novel drug substance which is at least one 3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine of the general formula 1 or 3-sulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidine of the general formula 2 or pharmaceutically acceptable salt and/or hydrate thereof, or a novel pharmaceutical composition, or a novel medicament.

According to the invention the preferable therapeutic kit is a therapeutic kit for treatment and prophylaxis of Alzheimer's and Huntington's diseases, psychotic disorders, schizophrenia, anxiety states and disorders, mental ability enhancing, hypoxia-ischemia, hypoglycemia, convulsive states, brain injuries, lathyrism, amyotrophic lateral sclerosis, obesity or insult comprising a novel drug substance, or a novel pharmaceutical composition, or a novel medicament.

Therapeutic kits for prophylaxis and treatment of various diseases pathogenesis of which is associated with serotonin 5-HT₆ receptors in humans and animals, among them neurological disorders, neurodegenerative and cognitive diseases in humans and animals, for prophylaxis and treatment of Alzheimer's disease, Huntington's disease, psychotic disorders, schizophrenia, hypoxia-ischemia, hypoglycemia, convulsive states, brain injuries, lathyrism, amyotrophic lateral sclerosis, obesity or insult, along with drug substances disclosed in the invention, may include other active ingredients such as: nonsteroidal anti-inflammatory drugs (Orthophene, Indomethacin, Ibuprophen and others); acetyl cholinesterase inhibitors (Tacrine, Amiridine, Fizostigmine, Aricept, Phenserine and others); estrogens (for example, Estradiol); NMDA-receptor antagonists (for example, Memantine, Neramexane); nootropic drugs (for example, Pyracetam, Fenibut and others); AMPA receptor modulators (for example, Ampalex); antagonists of cannabinoid receptors CB-1 (for example, Rimonabant); monoaminooxidase inhibitors MAO-B and/or MAO-A (for example, Rasagiline); antiamyloidogenic drugs (for example, Tramiprosate); lowering β-amyloidal neurotoxicity compounds (for example, Indole-3-propionic acid); γ- and/or β-secretase inhibitors; M1-muscarinic receptor agonists (for example, Cevimeline); metal helates (for example, Clioquinol); GABA(A) receptor antagonists (for example, CGP-36742); monoclonal antibodies (for example, Bapineuzumab); antioxidants; neurotrophic agents (for example, Cerebrolisine); antidepressants (for example, Imipramine, Sertraline and others) and others.

According to the invention the preferable therapeutic kit is a therapeutic kit for overweight lowering and obesity treatment, comprising a novel drug substance which is at least one 3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine of the general formula 1 and/or 3-sulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidine of the general formula 2 or pharmaceutically acceptable salt and/or hydrate thereof, or a novel pharmaceutical composition, or a novel medicament.

The therapeutic kit for overweight lowering and obesity treatment along with drug substances disclosed in the invention, may include other active ingredients such as: anorectic drugs (for example, Fepranon, Desopimon, Masindole), hormone drugs (for example, Tireoidine), hypolipidemic means such as fibrates (for example, Fenofibrate), statines (for example, Lovastatine, Simvastatine, Pravastatine and Probucol), and also hypoglycemic drugs (sulfonylurea—for example, Butamide, Glibenclamide; biguanidines—for example, Buformine, Metamorphine) and drugs with some other mechanism of action, such as cannabinoid CB-1 receptor antagonists (Rimonabant), inhibitors of norepinephrine and serotonin reuptake (Sibutramine), inhibitors of ferments of fatty acids synthesis (Orlistat) and others, along with antioxidants, food additives and others.

The subject of the present invention is also a method for prophylaxis and treatment of various diseases of central nervous system pathogenesis of which is associated with serotonin 5-HT₆ receptors in humans and animals, among them neurological disorders, neurodegenerative and cognitive diseases, anxiety states and disorders, mental ability enhancing, for overweight lowering and obesity treatment, which consists in introduction to a warm-blooded animal or a human being a novel drug substance, or a novel pharmaceutical composition, or a novel medicament, or a novel therapeutic kit comprising at least one 3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine of the general formula 1 or 3-sulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidine of the general formula 2, or pharmaceutically acceptable salt and/or hydrate thereof.

The medicaments could be introduced peroral or parenterally, for example, intravenously, subcutaneously, intraperitoneally or locally. Clinical dose of a drug substance, or a pharmaceutical composition, or medicament comprising at least one 3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine of the general formula 1 or 3-sulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidine of the general formula 2 or pharmaceutically acceptable salt and/or hydrate thereof, may be corrected depending on: therapeutic efficiency and bio-accessibility of active ingredients in patients' organism, rate of their exchange and removal from organism, and age, sex, and severity of patient's symptoms. Thus, the daily intake for adults normally being 10˜500 mg, preferably 50˜300 mg. Accordingly, the above effective doses are to be taken into consideration while preparing medicament of the present invention, each dose unit of the medicament contains 10˜500 mg of a drug substance of the general formulas 1, 2 or its pharmaceutically acceptable salt and/or hydrate, preferably 50˜300 mg. Following the instructions of physician or pharmacist, the medicaments may be taken several times over specified periods of time (preferably, from one to six times).

BEST EMBODIMENT OF THE INVENTION

The specific examples given below describe synthesis of 3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidines of the general formula 1,3-sulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidines of the general formula 2 and pharmaceutically acceptable salts and/or hydrates thereof, biological tests thereof. They illustrate but not limit the scope of the invention.

Example 1

The general method for preparation of substituted 3-sulfonyl-tetrahydropyrazolo[1,5-a]-pyrido-pyrimidines of the general formulas 1, 2.

A mixture of 0.005 mol of aminopyrazole 3 and 0.0055 mol of the corresponding β-dicarbonyl compound 4 in 5 ml of acetic acid was boiled for 4 hours. After cooling the solid precipitated was filtered off, washed with methanol and water. If necessary, the product was subjected to recrystallization from the proper solvent, or chromatographic purification or chromatographic separation. Yield of 3-sulfonyl-tetrahydropyrazolo[1,5-a]-pyrido-pyrimidines is within limits of 30%-85%. Table 2 represents some examples of novel 3-sulfonyl-tetrahydropyrazolo[1,5-a]pyrido-pyrimidines of the general formulas 1, 2, their LCMS and NMR data.

TABLE 2 Substituted 3-sulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidines of the general formula 1 and substituted 3-arylsulfonyl-5,6,7,8-tetrahydropyrazolo[1,5- a]pyrido[4,3-d]pyrimidines of the general formula 2 LCMS, m/z N ^(o) Formula Mol. w (M + 1) NMR 1(2)

375.47 376 1.1(1)

328.40 329 1.1(2)

342.42 343 1.1(3)

342.42 343 NMR-¹H (CDCl3): 8.45 (s, 1H); 8.12 (d, J = 8.0 Hz, 2H); 7.40-7.53 (m, 3H); 3.62 (s, 2H); 3.22 (t, J = 5.9 Hz, 2H); 2.83 (t, J = 5.9 Hz, 2H); 2.73 (s, 3H); 2.52 (s, 3H). 1.1(3) •HCl

378.88 343 1.1(4)

356.45 357 1.1(5)

362.84 363 1.1(6)

376.87 377 1.1(7)

376.87 377 1.1(8)

390.89 391 1.1(9)

428.51 429 1.1(10)

388.45 389 1.2(1)

360.46 361 1.2(2)

374.49 375 1.2(3)

374.49 375 NMR-¹H (CDCl3): 8.39 (s, 1H); 8.15 (d, J = 8.0 Hz, 2H); 7.36-7.55 (m, 3H); 3.61 (s, 2H); 3.21 (m, 2H); 2.83 (m, 2H); 2.59 (s, 3H); 2.51 (s, 3H). 1.2(3) •HCl

410.95 375 NMR-¹H (πMCO-D₆, 400 MΓμ) δ 11,76 (ω, 1H), 8,69 (c, 1H), 8,01 (_(M), 2H), 7,66 (_(M), 1H), 7,56 (_(M), 2H), 4,60 (ω, 1H), 4,37 (ω, 1H), 3,76 (ω, 1H), 3,50 (ω, 1H), 3,47 (ω, 2H), 2,94 (c, 3H), 2,61 (c, 3H). 1.2(4)

388.51 389 1.2(5)

394.90 395 1.2(6)

408.93 409 1.2(7)

408.93 409 1.2(8)

422.96 423 1.2(9)

428.94 393 (πMCO-D₆, 400 MΓμ) δ 11,70 (ω, 1H), 8,69 (c, 1H), 8,07 (_(M), 2H), 7,43 (_(T), J = 8,8 Γμ, 2H), 4,60 (ω, 1H), 4,38 (ω, 1H), 3,75 (ω, 1H), 3,51 (ω, 1H), 3,47 (ω, 2H), 2,94 (c, 3H), 2,61 (c, 3H). 1.2(10)

460.58 461 1.2(11)

450.59 451 2.1(1)

342.42 343 NMR-¹H (CDCl3): 8.25 (s, 1H); 8.13 (d, J = 8.0 Hz, 2H); 7.38-7.54 (m, 3H); 3.59 (s, 2H); 3.21 (t, J = 5.9 Hz, 2H); 2.82 (t, J = 5.9 Hz, 2H); 2.69 (s, 3H); 2.48 (s, 3H). 2.1(2)

378.88 343 NMR-¹H (DMSO-D₆): 11.63 (br.s, 1H); 9.21 (s, 1H); 8.01 (d, J = 8.0 Hz, 2H); 7.46-7.66 (m, 3H); 4.43-4.58 (br.m, 1H); 4.22-4.41 (br.m, 1H); 3.63-3.80 (br.m, 1H); 3.43-3.58 (br.m, 1H); 2.91 (s, 3H); 2.61 (s, 3H). 2.1(3)

413.33 377 2.2(1)

374.49 375 2.2(2)

410.95 375 NMR-¹H (CDCl3): 8.24 (s, 1H); 8.17 (d, J = 8.0 Hz, 2H); 7.40-7.54 (m, 3H); 3.58 (s, 2H); 3.20 (t, J = 6.3 Hz, 2H); 2.82 (t, J = 6.3 Hz, 2H); 2.56 (s, 3H); 2.49 (s, 3H). (πMCO-D₆, 400 MΓμ) δ 11,59 (ω, 1H), 9,25 (c, 1H), 8,01 (_(M), 2H) 7,67 (_(M), 1H) 7,57 (_(M), 2H), 4,51 (ω, 1H), 4,35 (ω, 1H), 3,75 (ω, 1H), 3,54 (ω, 1H), 3,30 (ω, 2H), 2,95 (c, 3H), 2,57 (c, 3H). 2.2(3)

428.94 393 NMR-¹H (πMCO-D₆, 400 MΓμ) δ 11,70 (m, 1H), 8,69 (c, 1H), 8,07 (_(M), 2H), 7,43 (_(T), J = 8,8 Γμ, 2H), 4,60 (ω, 1H), 4,38 (ω, 1H), 3,75 (ω, 1H), 3,51 (ω, 1H), 3,47 (ω, 2H), 2,94 (c, 3H), 2,61 (c, 3H). 2.2(4)

388.51 389

Example 2

Antagonistic activity test of compounds of the general formulas 1 and 2 towards 5-HT₆ receptors. Compounds of general formulas 1 and 2 were tested for their ability to prevent 5-HT₆ receptors activation by serotonin. HEK 293 cells (kidney cells of human's embryo) with artificially expressed 5-HT₆ receptor, activation of which by serotonin leads to increasing the concentration of intracellular cAMP were used. Intracellular cAMP content was determined using reagent kit LANCE cAMP (PerkinElmer) according to the method described by the manufacturer of the kit [http://las.perkinelmer.com/content/Manuals].

Effectiveness of compounds was estimated by their ability to reduce the content of intracellular cAMP induced by serotonin.

The tested substituted 3-sulfonyl-tetrahydropyrazolo[1,5-a]pyrido-pyrimidines of the general formulas 1, 2 (10 μM solutions) inhibited serotonin 5-HT₆ receptors at 80-100% and in the setting of functional assay exhibited high antagonistic activity.

Example 3

Activity test of serotonin 5-HT₆ receptor antagonists of the general formulas 1, 2 in the setting of competitive binding to serotonin 5-HT₆ receptors.

Screening of the disclosed compounds for their potential ability to interact with serotonin 5-HT₆ receptors was carried out by the method of radioligand binding. For this purpose membrane species were prepared from HeLa cells expressing recombinant human 5-HT₆ receptors, by means of cells homogenization in glass homogenizer with subsequent separation of plasmatic membranes from cell nucli, mitochondria's and cell wreckages by differential centrifugation. Determination of tested compounds binding to 5-HT₆ receptors was carried out according to the method described in [Monsma F J Jr, Shen Y, Ward R P, Hamblin M W and Sibley D R, Cloning and expression of a novel serotonin receptor with high affinity for tricyclic psychotropic drugs. Mol. Pharmacol. 43:320-327, 1993]. In the preferred embodiment the membrane preparations were incubated with the radioligand (1.5 nM [³H] Lysergic acid diethylamide) without and in the presence of investigated compounds for 120 min at 37° C. in the medium consisting of mM Tris-HCl, pH 7.4, 150 mM NaCl, 2 mM Ascorbic Acid, 0.001% BSA. After the incubation the samples were filtered in vacuo on glass-microfiber filters G/F (Millipor, USA), filters were washed three times with cold solution of the medium and radioactivity was measured by scintillation counter MicroBeta 340 (PerkinElmer, USA). Nonspecific binding which made up 30% of the overall binding was determined by incubation of the membrane preparations with radioligand in the presence of 5 μM Serotonin (5-HT). Methiothepin was used as a positive control. Binding of the tested compounds with the receptor was determined by their ability to displace the radioligand and was expressed in percent of displacement. The percent of displacement was calculated according to the following equation:

${{\%\mspace{14mu} I} = {\frac{{TA} - {CA}}{{TA} - {NA}} \star 100}},$ wherein: TA—was overall radioactivity in the presence of radioligand only, CA—was radioactivity in the presence of radioligand and tested compound and NA—was radioactivity in the presence of radioligand and Serotonin (5 μM). For the compounds investigated values of pKi (pKi=−1 g Ki) were calculated according to the equation shown below: K _(i) =IC ₅₀/(1+[L]/K _(D)) wherein: IC₅₀—the concentration of the tested compound in nM, at which it displaces 50% of the ligand bound to the receptor; [L]—ligand concentration; K_(D)—ligand dissociation constant.

The investigated substituted 3-sulfonyl-tetrahydropyrazolo[1,5-a]pyrido-pyrimidines of the general formulas 1, 2 exhibit high 5-HT₆ receptor affinity (Table 3).

Table 3. IC₅₀ and K_(i) Values of 3-Sulfonyl-Tetrahydropyrazolo[1,5-a]Pyrido-Pyrimidines of the General Formulas 1, 2 in the Setting of Competitive Binding to Serotonin 5-HT₆ Receptors

No IC₅₀, μM K_(i), μM 1.1(3) 0.013 0.0600 1.1(1) 0.00461 0.00214 1.2(2) 0.0166 0.0077 1.2(3) 0.0769 0.0357 1.2(6) 0.0239 0.0111 2.2(2) 0.801 0.372 2.2(3) >1

Example 4

Preparation of a medicament in a tabloid form. 1600 mg of starch, 1600 mg of ground lactose, 400 mg of talk and 1000 mg of 2-methylsulfanyl-5-methyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine hydrochloride 1.2(2) were mixed together and pressed into bar. The resultant bar was comminuted into granules and sifted through sieve to collect granules of 14-16 mesh. The granules thus obtained were shaped into tablets of suitable form weighing 560 mg each.

Example 5

Preparation of a medicament in the shape of capsules. 2-Methylsulfanyl-5-methyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine hydrochloride 1.2(2) and lactose powder were carefully mixed in ratio 2:1. The resultant powdery mixture was packed into gelatin capsules of suitable size by 300 mg to capsule.

Example 6

Preparation of a Medicament in Form of Compositions for Intramuscular, intraperitoneal or hypodermic injections. 500 mg of 2-methylsulfanyl-5-methyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine hydrochloride, 1.2(2) 300 mg of chlorobutanol, 2 ml of propylene glycol, and 100 ml of injectable water were mixed together. The resultant solution was filtered and placed into 1 ml ampoules, which were sealed and sterilized in autoclave.

Example 7

Nootropic action of the compounds of the general formulas 1 and 2 (enhancement of memory disturbed by Scopolamine) in the test “Passive Avoidance of mice in the Shuttle Chamber”. A shuttle chamber (Ugo Basile, Italy) consisted of two sections was used. The walls of one section were opaque while the other section had transparent cover. The sections were connected through a hole which could be overlapped by vertical door. The floor was made of transverse metal bars on which DC current impulses could be fed. Experiments were carried out in aged male mice of BALB/c line weighing 20-24 grams.

On the first day of testing 30 minutes before training mice were injected intraintestinally with physiological solution, Scopolamine (0.3 mg/kg) or Scopolamine in combination with active ingredient 1.2(2). Each group consisted of at least 8 animals. The animals were placed in the light section, and latent period of the first entry into the dark chamber was registered. Then the vertical door was closed and the animal was punished by 0.6 mA DC current for 3 seconds. After that the animal was taken back to its homecage. In 22-24 hours the same animal was placed again in the light section of the shuttle chamber and latent period of its first entry into the dark section, the total time of its stay in the light section and the number of entries into the dark section, was registered. Each monitoring lasted for 5 minutes.

Testing was carried out during the day time in isolated laboratory using white noise at level of about 70 decibel above human hearing threshold.

Scopolamine causes disturbance of training (memory loss) that results in increased latent period for the first entry into dark section, longer stay in light section, and in decreased number of entries into dark section.

The ability of compound 1.2(2) to enhance memory disturbed by Scopolamine is regarded as manifestation of its nootropic properties. The data obtained confirm nootropic action of active ingredient 1.2(2).

Example 8

Nootropic action (memory enhancement disturbed by MK-801) of compounds of general formulas 1 and 2 in the test “Passive Avoidance of mice in the Shuttle Chamber”. The testing was carried out as in example 7. On the first day of testing 30 minutes before training the mice were injected intraintestinally with physiological solution of MK-801 (0.1 mg/kg). In parallel, physiological solution of MK-801 in combination with active ingredient 1.2(2) was injected intraintestinally to independent groups of mice before training.

The results obtained testify the ability of active ingredient 1.1(3).HCl to produce nootropic effect.

Example 9

Anxiolytic (tranquilizing) action of compounds of general formulas 1 and 2 in the test “Mice Behavior in the Elevated Plus Maze”. The length of each arm of the maze is 30 cm, width is 5 cm, and height of walls is 15 cm. Two opposite arms are closed from both sides and end faces by transparent walls, the other two arms are lit and opened. A mouse was placed in the center of maze, and for the next five minutes the number of entries into opened and closed arms and the time spent in each type of arms were registered. These data were used to calculate the preference indexes for opened arms as ratio of the number of opened arm entries, as well as the total time spent there to the whole number of entries to all arms and the total time spent there. The animals usually avoid opened arms (the preference index is between 0.2 and 0.3). Compounds with tranquilizing action increase this index up to 0.5-0.6 or even more and reduce the number of defecations without changing the overall motion activity of the mice (the total number of entries to the arms).

The results obtained testify that active ingredient 1.2(2) exhibits anxiolytic (tranquilizing) action which is comparable with the activity of Buspirone and Lorasepam.

INDUSTRIAL APPLICABILITY

The invention could be use in medicine, veterinary, biochemistry. 

The invention claimed is:
 1. A substituted 3-arylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine of the general formula 1 or substituted 3-arylsulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidine of the general formula 2 compound, or a pharmaceutically acceptable salt thereof,

wherein: Ar is an optionally substituted aryl or an optionally substituted heterocyclyl; R¹ is hydrogen, an optionally substituted lower C₁-C₃ alkyl, substituted hydroxyl group, substituted sulfanyl group; R² is hydrogen or an optionally substituted C₁-C₃ alkyl; R³ is hydrogen, an optionally substituted C₁-C₃ alkyl or tert.-butyloxycarbonyl.
 2. The compound according to claim 1, representing substituted 3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine of the general formula 1.1 or substituted 3-phenylsulfonyl-5,6,7,8-tetrahydropyrazolo[1,5-a]pyrido[4,3-d]pyrimidine of the general formula 2.1, or a pharmaceutically acceptable salt thereof,

wherein: R¹, R² and R³ have the above meanings; R⁴ is hydrogen, one or two optionally identical halogens, hydroxyl group optionally substituted with C₁-C₃ alkyl.
 3. The compound of claim 2 of general formula 1.2 or general formula 2.2, or a pharmaceutically acceptable salt thereof,

wherein: R², R³ and R⁴ have the above meanings.
 4. The compound of claim 1 selected from the group, consisting of: 2-methyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(1), 2,5-dimethyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(2), 2,7-dimethyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(3), 2,5,7-trimethyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(4), 2-methyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(5), 2,5-dimethyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(6), 2,7-dimethyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(7), 2,5,7-trimethyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.1(8), 2-methylsulfanyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(1), 5-methyl-2-methylsulfanyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(2), 7-methyl-2-methylsulfanyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(3), 5,7-dimethyl-2-methylsulfanyl-3-phenylsulfonyl-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(4), 2-methylsulfanyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(5), 5-methyl-2-methylsulfanyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(6), 7-methyl-2-methylsulfanyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(7), and 5,7-dimethyl-2-methylsulfanyl-3-(3-chlorophenylsulfonyl)-6,7,8,9-tetrahydropyrazolo[1,5-a]pyrido[4,3-e]pyrimidine 1.2(8), or a pharmaceutically acceptable salt thereof,


5. A method of serotonin 5-HT₆ receptors antagonizing comprising administering into the cell the compounds of the general formula 1 and 2 or pharmaceutically acceptable salts thereof

wherein: Ar is optionally substituted aryl or optionally substituted heterocyclyl; R¹ is hydrogen, optionally substituted lower C₁-C₃ alkyl, substituted hydroxyl group, substituted sulfanyl group; R² is hydrogen or optionally substituted C₁-C₃ alkyl; R³ is hydrogen, optionally substituted C₁-C₃ alkyl or tert.-butyloxycarbonyl.
 6. “Molecular tools” for investigation of peculiarities of physiologically active compounds possessing the property to inhibit serotonin 5-HT₆ receptors are the compounds of claim 1 of the general formula 1 and 2 or pharmaceutically acceptable salts thereof.
 7. A formulation comprising compounds of the general formula 1 and 2 or pharmaceutically acceptable salts thereof, of claim 1 and pharmaceutically acceptable carriers, including inert excipients and/or solvents.
 8. The formulation according to claim 7, which is in the form of tablet, capsule, or injectable liquid placed in pharmaceutically acceptable packing.
 9. A method of treating a disease, pathogenesis of which is associated with 5-HT₆ receptors, comprising administering to a subject a pharmaceutically effective amount of a compound of general formula 1 or 2, or a pharmaceutically acceptable salt thereof,

wherein: Ar is an optionally substituted aryl or an optionally substituted heterocyclyl; R¹ is hydrogen, an optionally substituted lower C₁-C₃alkyl, a substituted hydroxy group, a substituted sulfanyl group; R² is hydrogen or an optionally substituted C₁-C₃alkyl; R³ is hydrogen, an optionally substituted C₁-C₃alkyl or tert.-butyloxycarbonyl.
 10. The method according to claim 9, wherein said disease, selected from the group, consisting of: Alzheimer's disease, Parkinson's disease, Huntington's disease, psychotic disorder, schizophrenia, anxiety disorder, hypoxia-ischemia, hypoglycemia, convulsive state, cerebral damage, lathyrism, amyotrophic lateral sclerosis, obesity, hyperkinetic disorder, and a mental ability enhancing.
 11. A therapeutic cocktail treating a disease, pathogenesis of which is associated with 5-HT₆ receptors, comprising a pharmaceutically effective amount of a medicament including the compounds of the general formulas 1 or 2, or pharmaceutically acceptable salt thereof and pharmaceutically acceptable carriers, including inert excipients and/or solvents placed in a pharmaceutically acceptable packing,

wherein: Ar is an optionally substituted aryl or optionally substituted heterocyclyl; R¹ is hydrogen, an optionally substituted lower C₁-C₃alkyl, a substituted hydroxyl group, a substituted sulfanyl group; R² is hydrogen or an optionally substituted C₁-C₃alkyl; R³ is hydrogen, an optionally substituted C₁-C₃alkyl or tert.-butyloxycarbonyl.
 12. A method of treating a disease, pathogenesis of which is associated with 5-HT₆ receptors, comprising administering to a subject an effective amount of the therapeutic cocktail according to claim
 11. 13. The method according to claim 12, wherein said disease, selected from the group, consisting of: Alzheimer's disease, Parkinson's disease, Huntington's disease, psychotic disorder, schizophrenia, anxiety disorder, hypoxia-ischemia, hypoglycemia, convulsive state, cerebral damage, lathyrism, amyotrophic lateral sclerosis, and obesity. 